In chemotherapies of cancers, a variety of anticancer agents including antimitotic agents such as taxane and vinca alkaloid, topoisomerase inhibitors, alkylating agents and the like have been used. These agents have side effects such as bone marrow toxicity and neuropathy, a problem of drug resistance and the like. Therefore, novel anticancer agents which have improvement in the above problems have so far been desired.
It is known that thiadiazoline derivatives have inhibitory activity against transcription factor STAT6 activation, antagonistic action of integrin, and the control of insect or acarid pests (Japanese Published Unexamined Patent Application No. 2000-229959, WO01/56994, U.S. Pat. No. 6,235,762). In addition, it is known that the derivatives have antibacterial activity, ACE inhibitory activity and the like [J. Bangladesh Chem. Soc., Vol. 5, p. 127 (1992), WO93/22311, Japanese Published Unexamined Patent Application No. 62-53976 (1987)].